From burgers and steaks to pizzas to soups, it's surprising how many dishes taste better with the sweet, nutty tang that caramelised onions offer. The trouble is, they can take upwards of an hour to make, much too long for most weeknight meals. So, when you have some time to spare, cook up a big batch and freeze them. You can freeze them in different portions using ice cube trays, muffin tins, freezer bags, or whatever you want.